Indirect interaction of magnetic domain walls

Abstract

1 Introduction Magnetic domain walls (DWs) have attracted a lot of attention as important elements of new magnetoelectronic devices [1 -3]. In particular, it was demonstrated recently that they can be used in a new type of memory device (the racetrack memory) effectively controlled by an electric current [4,5]. On the other hand, the DW can be viewed as a kind of local imperfection in an ordered magnetic system, like an impurity or defect. The substantial difference is that DWs can move and therefore they can be relatively easily put into motion by an external field or electric current, and also by an interaction between them.A great amount of theoretical and experimental work was dedicated to studying the resistance of DWs, the current-induced spin torque, the dynamics of DW motion, and other effects related to a single DW strongly coupled to the electron system [3,6,7]. When the density of DWs increases, it is important to include into these considerations the effects of their interaction. It has already been demonstrated [8 -11] that an electric current in a magnetic wire with DWs influences the DW interaction, so that by using a current the DW coupling can be controlled, and the dynamics of strongly coupled DWs can be affected.In this work we consider in detail the indirect exchange coupling between the DWs in equilibrium. Essentially, the analysis of such interaction is the first necessary step to understand the basic mechanisms of DW interactions.

Local spin transfer torque and magnetoresistance in domain walls with variable width

“…Previous studies have shown that scattering from successive sharp DWs can induce non-aligned spin densities which lower the threshold for current induced DW motion and lead to ordering of the DWs. [34][35][36][37] This paper is organized as follows: In Sec. II we present the model and theory to find the STTs in magnetic DWs constrained in nano-contacts, which is used in Sec.…”

Negative differential magnetoresistance in ferromagnetic wires with domain walls

“…6 The interaction of the current electrons with the domain wall can even induce interaction effects between the DWs. [7][8][9][10] In this paper we wish to address effects which occur when the domain wall is pinned. If the current is not large enough to cause lateral motion of the DW through the wire it is nevertheless possible for the DW to experience oscillatory motion.…”

Dynamics of the polarization of a pinned domain wall in a magnetic nanowire

“…1 Introduction Since the possibility of moving magnetic domain walls (DWs) in nanowires due to electric currents was realized, the behaviour of DWs in wires subject to a variety of pulses, currents, fields and pinning forces has been extensively studied [1,2,3,4,5,6]. Electrons passing a DW transfer momentum and spin with the DW, which results in a modification of the resistivity of the wire and the motion of the DW [7,8,9].…”